/*
gps坐标转高德坐标系
 */
angular.module('driver')
.factory('Transfer', function() {
  var pi = 3.14159265358979324;
  var a = 6378245.0;
  var ee = 0.00669342162296594323;

  function transform(wgLat, wgLon)
  {
      if (outOfChina(wgLat, wgLon))
      {
          return {lat: wgLat, lng: wgLon};
      }
      var dLat = transformLat(wgLon - 105.0, wgLat - 35.0);
      var dLon = transformLon(wgLon - 105.0, wgLat - 35.0);
      var radLat = wgLat / 180.0 * pi;
      var magic = Math.sin(radLat);
      magic = 1 - ee * magic * magic;
      var sqrtMagic = Math.sqrt(magic);
      dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
      dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);
      var mgLat = wgLat + dLat;
      var mgLon = wgLon + dLon;

      return {lat: mgLat, lng: mgLon};
  }
  function outOfChina(lat, lon)
  {
      if (lon < 72.004 || lon > 137.8347)
          return true;
      if (lat < 0.8293 || lat > 55.8271)
          return true;
      return false;
  }

  function transformLat(x, y)
  {
      var ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
      ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
      ret += (20.0 * Math.sin(y * pi) + 40.0 * Math.sin(y / 3.0 * pi)) * 2.0 / 3.0;
      ret += (160.0 * Math.sin(y / 12.0 * pi) + 320 * Math.sin(y * pi / 30.0)) * 2.0 / 3.0;
      return ret;
  }

  function transformLon(x, y)
  {
      var ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
      ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
      ret += (20.0 * Math.sin(x * pi) + 40.0 * Math.sin(x / 3.0 * pi)) * 2.0 / 3.0;
      ret += (150.0 * Math.sin(x / 12.0 * pi) + 300.0 * Math.sin(x / 30.0 * pi)) * 2.0 / 3.0;
      return ret;
  }

  return {
    transfer: function(lat, lng) {
      return transform(lat, lng);
    }
  };
});
